Household windows are conventionally cleaned manually, and sometimes window cleaning is performed by opening or removing the windows. For cleaning exterior surfaces of windows of tall buildings, a suspension rack provided by a cleaning service provider is suspended outside the building, the suspension rack is controlled to move up or down by a motor, and the exteriors of the windows are cleaned using brushes or water jet streams. However, the suspension rack can easily be tipped off balance, and is susceptible to being swung about by high winds, and thus can pose safety risks to cleaning service personnel. In addition, accidents, such as the cleaning service personnel slipping or cleaning equipment falling onto passersby below, may result from cleaning the windows with excessive water pressure, so that only low-pressure water streams are allowed, preventing the windows from being thoroughly cleaned. Thus, cleaning robots have been proposed to address the issues arising from cleaning windows manually.
During operation of a cleaning robot of the prior art, when the robot encounters an obstacle attached to a window, the robot will be tilted or entirely lifted from the window surface, causing air leakage of a suction disk and the failure of the robot to remain attached to the window surface. Further, given unsuitable distribution of the force between the moving wheels or a track belt and a suction disk, the robot is prone to losing traction and mobility, or unable to apply a wiping force sufficient to perform effective window cleaning.
A conventional cleaning robot cleans windows using a brush or cloth that is primarily suited for cleaning mild dirt and dust. If the window is stained or soiled with grime that cannot be easily removed, the wiping operation provided by such cleaning robot is unable to clean the window effectively. Therefore, there is a need for an improved solution to existing cleaning robots for enhancing the cleaning performance and efficiency.